Inappropriate utilization of Emergency Departments (ED) services may result in compromised management of patients requiring true emergency treatment. Significant attendance of non-emergency cases in ED was found in several countries. A cross-sectional study was conducted in Universiti Sains Malaysia Hospital (HUSM) to determine the proportion of the inappropriate cases and the utilization pattern by time (over 24 hours and within a week) and by diagnoses. A sample of 350 cases was randomly selected from ED-HUSM register of the year 2000. A decision flowchart, which was adopted from 4 guidelines, was applied to classify appropriate and inappropriate cases. There were 55% inappropriate cases in this study. The inappropriate cases increased considerably in early morning, late evening, during the weekend and early part of the week. Most common diagnoses of inappropriate cases were upper respiratory tract infections, mild acute gastroenteritis and urinary tract infections. Considerable attendance of inappropriate cases calls for interventions.